US1595603A - Apparatus for recovering phenols from ammoniacal liquor - Google Patents

Description

Aug. l0 1926.

LE RoY w. HEFFNER ET AL APPARATUS FOR REC'OVERING PHENOLS FROM AMMONIACAL LIQUOR- mmv lNvTORs ATTORNEYS v LE ROY W. HEFFNER ET AL APPARATUS POR RECOVERING PHENOLS FROM AMMONIACAL LIQUOR 4 Sheets-Sheet 5 originar Filed De. 1s, 1924 N www@ SAQ bevi:

mvENToRs if, f

f B i g ATTORNEY:

Aug. 1o 1926; Y 1,595,603 LE ROY W. HEFFNER ET A..

:APPARATUS lFOR RECOVERING PHENOLS FROM AMMONIACAL LIIQUOR` Original Filed De. 16,- 1924 4 Sheets-Sheet 4 elevation an.

i any vapors formed Patented 10, 19126. UNITED STAT Es PATENT oFF-ICE.

LE BOY WILBUB HEFFNEB, OF EAST-NOIBBJSTOWNl TOWNSHIP, MONTGOMERY COUNTY,

AND WILLIAM TIDDY,

0F JEFFEBSONVILLE, PENNSYLVANIA, ASSIGNOBS TO BAINEY-WOOD PROCESS CORPORATION, AOIE YORK, N. Y., A CORPORATION 0F DELAWARE.'

Y APPARATUS FOR RECOVEBING PHENOLS FROM AMONIACAL originalapplicati@ mea member' 1e, 1924, serial application led December This invention refers to an improved apparatus for recovering phenols from am- -moniacal gas liquor, etc., and particularly to an apparatus for carrying outthe process of our prior application Serial No. 7 56,194 filed December 16, 1924, the present application being a division of such Vapplication (now Patent No. 1,566,796).

The invention is illustrated in the accompanying drawings, showing certain embodiments thereof, butthe invention is not limited thereto.

'In the drawings, Fig. 1 shows an still parts being broken awayt-o show the interior construction', Fig. 2 illustrates, somewhatconventionally and diagrammatically, another arrangement of apparatus in the nature of a iow sheet; Fig. 3 shows in aqua-ammonia apparatus, adapted for carrying out the invention; Fig. 4 showsV a modified apparatus; and Fig. 5 shows still another modified type of the apparatus.

The apparatus of Fig. 1 includes au ammonia still having heating means suicient to maintain the temperature of thevapors and liquid at the'top of the free ammonia still sufficiently high e. g., around 98 to 103 C. Y

The still includes a prehcater 1, heated by steam and having a gas liquor feed pipe 2, and a supply pipe 3 for conveying the preheated liquor to the top of the freeA ammonia still 6.- A vent pipe 3? isprovided for the escape to the top of the still 6` of in the preheater. The still has the usual lime leg S, having steam heating coil 14. The l 10 is connected with the lime leg through the'connecting pipe 9 and the ammonia from the fixed ammonia still escapes to the bot-l tom of the free ammonia still through the pipe 11. The stillillustrated in Fig. 1 may, in practice, be provided with an alkali washer, or other phenol absorber, etc., such as illustrated in- Figs. 2 and 3.

The still illustrated has the vapor outlet pipe 7 for the ammonical vapors from the still. This pipe has two branches, one

ammonia branch 7a with suitable regulating valve.

therein leading directly to the saturator for .through the pipe fixed ammonia still manon.

No. 756,164, Patent No. 1,566,796. Divided and thi! 22, 1925. Serial No. '77,100. Y

leading directly to a phenol absorber for separating the phenolic compounds from the ammoniacal gases before they are further used. A`nother branch 7" having regu- .lating valve therein, connects with the reflux condenser or cooler or'dephlegmator 7, and the vapors from ,this reflui:l cooler. escape 7 d directly to the saturator, or to a phenol absorber and then to a-sat- 'urator or vammonia absorber. A return pipe 7e conveys the condensate from the'relux cooler back to the free ammonia still. The reflux condenser or dephlegmator is arranged for indirect contact of the vapors with the cooling liquor. For example, the cooling liquid, such as water at a regulated temperature and in regulated amounts may flow around tubes or pipes through whlch the vapors ascend, so that the vapors will be cooled, and vso thatv the condensate therefrom will flow downwardly and collect incomes in Contact with lime and where the Alime reacts with the ixedammon'ia compounds to set free the ammonia, the ammonia thus set free is driven off inthe fixed therefrom.

' ammonia, largely if not completely as al n.

Aammonia still 10 and the ammonia 'vapors passed Y still and upwardly therethrough, in the formation and the carrying o phenol compounds as phenolateS.

Where the gasliquor treated is ammonia, this ammonia may in itself be sufficient to eiect the removal'of a large into the bottomof thefree ammonla assisting if of the rich in the liquor is not suliicient, additional ammonia may be supplied to the still, suicient to eli'ect the removal of an increased amount of the phenolicf'compounds or even to effect substantially complete removal thereof.

It will` be noted that the free ammonia still of Fig. 1 is shown broken away at an intermediate point to indicate an indefinite height of the still. The still may be of the usual height and with the usual number of sections. In order, however` to provide for additional contact of the ammoniavapors with the preheated liquor, the still may advantageously have added sections, in addition to those of theordinaryl still, and these will provide an increased scrubbing action of the ammonia vapors rising upwardly through the still through the scrubbing sections and the preheated liquor iiowing downwardly through these sections and through the free ammonia still. By increasing this countercurrent flow and scrubbing action, and by maintaining the temperature of both the liquor and the gases and vapors above 98 C., a more complete driving oli' and removal of phenolic compounds with the ammonia can be obtained. Y

Where the temperature of the vapors escaping from the top of the free ammonia still is not too high, e. g. is at 103 C. or below, theymay be passed directly to a saturator or to a phenol absorber and then to should be sufficiently high to prevent reabsorptlon of phenolic compounds in the liquor, i. e. it should be at 98 C; or higher.

In the apparatus of Fig. 2 the preheater and the free and fixed ammonia stills are given the same reference characters as in Fig. 1, and the still is operated in a similar way, except for the modications described below.

In Fig. 2 a separate countercurrent scrubber is provided between the gas liquor preheater and the free ammonia still and the preheated liquor is subjected to the total vapors coming from the ammonia still. That is, the gas liquor from the preheater 1 passes through the pipe 3 to the top of the counter'current scrubber 4 and passes downwardly therethrough, the resulting liquor then passing through the pipe 3a to the top of the free ammonia still. From the top of the free ammonia still the vapors of ammonia, etc., pass through the pipe 5 'to the bottom of the countercurrent scrubber 4 and upwardly therethrough countercurrent to the down-flowing preheated liquor. The ammoniacal vapors from the r top of the, countercurrent scrubber 4 may pass through the pipe 18 directly to a saturator or through the branch pipe 19 to a phenol absorber, such as an alkali washer 20. In this absorber they are brought into intimate contact with an absorbent, e. g. a caustic alkali solution which will decompose the ammonium phenolate and form alkali phenolate. .The remaina saturator. Where the vapors are at a ing ammoniacal vapors then pass through higher temperature and contain an increased amount of water vapor, they may advantageously be subjected to a regulated condensing or-reflfuxing operation in the reflux condenser or dephle ator 7 g and the temperature cooled to 103 C. or lower with return 4of the excess water vapor to the still in a condensed form. The vapors can be cooled to a temperature below '103 C. but should not be cooled to a temperature below 98 C., and the liquor in the bottom of the 'vdephlegmaton and returning to the fstill,

should not be cooled below 98 C. The prov1 s1on of a dephlegmator, as illustrated in Flg. 1, enables the temperature of the escap- -ing vapors to be regulated and controlled, to

remove excess water vapor therefrom, while neverthelesspermitting the escape of vphenollc compounds with thela1nmonia,while the provision of a direct connection '7a per-` mits the vapors from the still to be passed directly to a saturator or to a phenol absorber without additionaldephlegmation, in whlch case the temperature of the liquor and vapors in the top o f the free ammonia still ltself, or in the top of the added scrubbing sect-ion superimposed thereon, will determine the moisture content of the escaping vapors. The ltemperature of both the liquor and the vapors at the'outlet from the still the pipe 21 to the condenser or dephlegnuator- 22 in which they are subjected to cooling and a considerable part of the water vapor separated out as ammoniacal liquor which .returns through the pipe 23 kto the bottom of the countercurrent scrubber 4. The purified and dried ammonia gas then passes through the pipe 24 and the pipe 18 to the saturator or to other place of treatment or use. The alkali phenolate solution collecting in the washer 20 can be drawn olf through the outlet pipe 27 having regulating valve 28 therein. By closing the valves in the pipes 19 and 24, the vapors can be passed directly to a saturator. 1

In Fig. 2 it will be noted that a phenol absorber is arranged so that the vapors passing from the free ammonia still 6 to the scrubber 4 may be passed through the absorber, or b -passed directly from the still to the scrub r. The connecting pipe 5 has a direct branch A5, with valve therein, by

ration of phenolic compounds therein, a er which the purified ammonia 'gasespass through the branch pipe 5 to the scrubber.

It also has a branch 5* withV valve 980 C. or higher.

driven off to a large extent This phenol absorber may contain an alkali solution to break up thev ammonium phenolate and form alkali phenolate which may be removed from time to time through the outlet pipe 5e when the solution is to be replenished.

In the operation of the apparatus of Fig. 2 the gas liquor is first preheated to a temperature of 98 C. or higher in the preheater 1 and then passes into the scrubber 4 Where its temperature is maintained at In this scrubber it is subjected to the scrubbing action of the vapors escaping from the top of the free ammonia still through the pipe 5. These vapors may include ammonia together with ammonium phenolate or they may have the phenolate removed therefrom by the absorber 5d. The maintenance of the temperature .of the scrubber at' 98o C. or higher insures that any ammonium phenolate will not be condensed and held in the scrubber but will be if not comthe ammonia escaping through The gas liquor thus freed from a considerable part of its ammonia and phenolate enters the top of the free ammonia still Where the usual distilling operation takes place, the greater part or all of the remaining free ammonia being set free in the free ammonia still and the fixed ammonia being then set free by the action of lime and distilled in the fixed ammonia still. The ammonia set free in the fixed ammonia still passes upwardly through the free 'ammonia still and serves to assist in carrying away pletely with the pipe 18.

any remaining phenolic compounds which the liquor contains at this place. By providing a suicient amount of ammonia in the-still or in the scrubber or in both it is possible to effect substantially complete removal of phenolic compounds so that the liquor that comes in contact with the'lime in the lime leg will contain no phenolic compounds. Inasmuch as such compounds if present in the liquor coming in contact with the lime will combine with the lime to form calcium phenolate and will be held and prevented from volatilizin'g, it is important to effect removal more or less completely of the phenolic compounds from the liquor 'before it comes in contact with the lime.

By operating the phenol absorbers at a high temperature, -for example, by using a strong caustic soda solution and heating it to a high temperature, absorption or condensation of Water lvapor is prevented, and

a strong solution of sodium Yphenolate can`r be obtained. In the case of the phenol absorber 5, VIthis maintenance of the absorbent solution at a high temperature prevents cooling of the ammonia gases entering the bottom of the scrubber 4. In the case of the phenol absorber20, the hot ammonia andjadmixed water vapor pass to the delWater vapor. The condensed Water together with absorbed and condensed ammonia pass back to the countercurrent scrubber as al-l ready pointed out. v In addition a further v amount of ammonia gas can if desired be returnedV either to the countercurrent scrubber or to the free ammonia still to increase the amount of phenols driven off, and to elect substantially complete removal of phenols from the liquor. In the apparatus illustrated in Fig. 2 the lime leg is heated by the steam coil 14 having regulating valve 17 therein and the fixed ammonia still by the steam coil 15 having regulating valve 16. An outlet pipe'for the Waste liquor from the fixed ammonia. still is indicated at 12 having valve 13 therein.

lVhen the alkali solution in the Washers becomes charged with phenols, they may be drawn off yand replenished, and the phenol can be recovered therefrom in any suitable manner, as for example, by acidifying the solution and distilling off the phenol, or the alkali phenolate may be utilized for other purposes.

In the apparatus of Fig. 2, the countercurrent scrubber 4- may be-of any suitable construction which will permit effective 'countercurrent cont-act between the gases vprovision of a separate scrubber, however,

makes possible the countercurrent treatment of the preheated gas liquor before it reaches the usual free ammonia still, as well as'the freeing of the vapors they enter the separate scrubber.

Fig. 3 illustrates a modified apparatus for producing aqua-ammonia and at the same time recovering a large percentage or all of the phenol from the gas liquor.

Gas. liquor flows from the .feed tank 102 into the scrubber 104 and from thence into the preheater 101 Where the liquor is heated to a temperature approximately 98 C. to 99 C. The hot liquor then passes through the pipe 103 and 105 into the free ammonia or volatile still 106, or, if desired, the valve 112 may be closed and the hot liquor pumped under positive pressure by the liquor pump 113. The free ammonia still 106 is maintained at a temperature such that both the liquor and 98 C. Most of the free ammonia and a large percentage of the phenol as ammonium phenolate is volatilized in the still 10G,4

vapors are at or above from phenol before liquor from the fixed ammonia still.

The vapors containing ammonia and phenolate from the free ammonia still pass through a pipe 107 into the alkali washer 120 where the ammonium phenolatev is decomposed and the phenol removed `from the vapors in the form of alkali phenolate,

which is withdrawn from time to time and the phenol recovered as above described. The phenol-free vapors from the alkali washer pass through pipe 121 into the ammonia condenser 122 where most of the Water is condensed. out and flows into the evaporators 118 through pipe 117. The ammonia from the condenser passes into the water washerl23 through the pipe 124 and the ammonia dissolved in the condensate is led from the evaporators 118 into the water washer through pipe 125.

The ammonia is then Washed asv usual withoil in the oil washer 126, with the monitor 127, and is filtered in the charcoal filter 128 and bone black filter 129 and finallypassed into the absorbers 130 and 131, where it is absorbed in distilled water supplied from the tank 132.

It will be seen that the apparatus of Fig. 3 differs from the usual aqua-ammonia plant in that the dephlegmator is removed from the top ,of the ammonia still and an alkali washer is introduced between the top of the ammonia still and the dephlegmator or condenser.. This permits the free ammonia still to be operated at -a higher temperature and without refiuxing and return of water and phenolate to the still, and permits the ammonia with admixed water va.

por and phenolate to pass over to the alkali washer Where. the phenolate is decomposed and the` phenol absorbed as alkali phenolate before the ammonia is subjected to condensation to remove the admixed water vapor therefrom. This removal of the condensers to a. distance from the still and the introduction of an alkali washer between' the still and condenser, together with the operation of the still itself at a sutliciently high temperature, permits the phenolate to be removed from the still with the ammonia and to be recovered before the ammonia is subjected to condensation to remove the water vapor therefrom. By opera-ting the alkali washer at a high temperature, the water vapor ispreven'ted from condensing in washer and from diluting the alkali solution.

While'the apparatus illustrated in Figq temperature above 98 C. so as to avoid reabsorptin of ammonium phenolates. Where such a dephlegmator is provided, a temperature considerably higher than 98 C. can be maintained in the free ammonia still, and the dephlegmator can be relied p,

upon to cool the vapors down to a temperature such that excessive amounts of water vapor are removed, but lammonium phenolate nevertheless permitted to pass off with the ammonia.

The apparatus of Fig. 4 is a modified apparatus in which thepreheated'gas liquor is brought into contact with the total ammonia evolved from the gas liquor without recycling of ammonia vapor. In this figure, the same reference numerals are used as in Figs. l and 2 for corresponding parts of the apparatus, with the sufiix b appended thereto in certain cases.

In this apparatus, the gas liquor from the preheater charge passes at av temperature of 98 C. or higher to the top of the free ammonia still 6b and flows downwardly therethrough. From the bottom of the free ammonia still the liquor flows through 'the pipe 3c to the to of the countercurrent scrubber 4, in which the liquor is maintained at a temperature of 98 C. or higher. The liquor flows downwardly through the scrubber and leaves the base of the scrubber through the pipe 3d, through which it is pumped by the pump 3e, to the lime leg 8 of the ammonia still, and then through the regular fixed still. The ammoniacal vapor from the free ammonia still passes off through the pipe 5 to the bottom of the countercurrent scrubber 4 and passes upwardly therethrough countercurrent to the liquor.

The general arrangement-of the apparatus of Fig. 4 is similar to that of Fig. 2 except,

-for the different arrangement 'of the countercurrent scrubber with reference to the ammonia still. In the apparatus of Fig. 2, the preheated liquor first enters the scrubber and then passes tothe free ammonia still; while in the apparatus of Fig. 4, the liquor is first preheated and passes to the free ammonia still and subsequently toa countercurrent scrubbing before it enters the lime leg. In the apparatus of Fig. 4,v the ammonia set free in the fixed ammonia stillpasses v upwardly through the free ammonia still and 4the ammoniaeall' vapors'are takenoi mi lphenolate. The p is low or is insuliicient to etect complete be most readily carried o removal of phenolic4 compounds as ammo- 18 bythe am nium phenolate, additional ammonia may be the scrubber. supplied to the still to increase the phenolic of Fig. 5 is othe recovery. Even Without the addition of described in connection ammonia, however, an important recovery of Fig. 2. of phenols can be obtained, particularly We claim:`

Which is itself rich in am- 1. An apparatus monia. v Where the ammonia content in the comprising an amm v Still is to be increased, the ammonia may admeans su vantageously be that which is recovered upper `porti troni'v the process itself, after purification sufficiently high t from admixed phenolate. We do nothowlpounds with th over, claim herein apparatus for carrying out sorber arranged to re a .cyclic process in which the ammonia is so pounds from from the top of the free ammonia still at a of a separa temperature suliiciently high to insure the operation, carrying ott of phenolic compounds'with the suiiicient ammonia ammonia, i. e., a temperature of 98 C. tially all or higher. The Ytotal amount of ammonia is driven off so that they may and so thatthe Waste liquor will be freed from objectiona Even Without 'suc however, and

is itself rich in ammo the present invention permits` of important amounts ot liquor which are nord. The present des for a new ot phenolsmay the\\extent that the d, thetvvaste liquor is le'phenolic constituthen caused to pass countercurrent to the liquor in the scrubber 4.

A phenol absorber 5d vmay be provided in constituents. Fig. 4 similar to the phenol absorber 5d in of ammonia,

Fig 2. By proper manipulation of the the gas liquor valves in the pipe 5a, 5, and 5, the phenol apparatus of absorber can be omitted or included as dethe sired. When the gases from the free am-v phenol from thogas monia still are passed throughthe phenol mally lostancl notrrecovere absorber (containing for example,'a solution apparatus, ot caustic soda), the ammonium phenolate means by w will be decomposed, the phenol will be combe effected, and, to bined with the caustic soda as sodium phenols are recovere phenolate, and the ammonia set free will be freed from Aobjectionab carried along with the other ammonia into ents. the countercurrent scrubber." By purifying The modified apparat theammonia in this Way, the liquorin the is similar to the appara scrubber will be subjectedto the counterc'urthe additi n of a dephlegmator rent action of the ammonia and, by .mainbetween taining the scrubber at a temperature of 98 scrubber. f C. y or higher, further opportunity is preby means of the pipe sented for the ammonia to combine with and passpipe 51 is pro carry away the phenolic compounds as. therein. The pipe 5f enolic compounds car'- The arrangement ofpip'e ried over from the scrubber through the that the o'coming gases lime 18 can betreated, for example, asV debe either by-passed scribed in connection with Fig. 2 above. or passed throu Where the amount of phenolic compounds pipe 5m connects t in the liquor is small With reference to ammator with the top of the scrubber. monia content, the phenol absorber 5d may In the operation of the treeY a he omitted .and the ammonia may be sut` still at the highert ficient inf. such case to effect substantially 103 C., complete removal of the phenol. Withthe vapor passes with phenol absorber available for vuse where detop of thel still. sired, and with the arrangement ofFig. 4, pors are passed through substantially complete removal of phenolic 5h, this Water `compounds can be effected, particularly along with the where the gas liquor is high in ammonia; practically and this can be elected Without recycling of the top of the of the scrubber. In the apparatus of Fig. 3, as well as in from the bottom 4of the Y through the pipe 5m in normal ammonia content of the gas liquor scrubber Where the ph RIDIDO'DIB..

the apparatus of Figs. 1, 2 or 4, where the vfrom vgas liquor of the pheno hich the recovery t e free ammonia st This dephlegm emperatures,` e. g.,

rable amount of Water the other vapors from the When the oli'coming vathe dephlegmator largely condensed unds, leaving 'phenol compo to pass from the vapors purified and returned to the still, inasmuch condenser or deph as such cyclic apparatus forms the subject Water vapor romt te application. With such cyclicl it is readily possible to recycle to insure that substanlic compounds will be be recovered, from the still ble phenolic h recycling particularly if nia, the

us shown in Fig. 5 tus in Fig. 2, with 5h arranged ill and the ator is connected and 5, and a byded having valve 5k has valve 5g therein. s and valves is such from the still may the scrubber, the dephlegmator.. A he bottom of the dephlegmmonia around for treating gas liquor, onia still having heating heat vthe liquor in the on of the still to a temperature o drive oft` phenolic coma phenol abmove phenolic comfrom the still, and a vor for .removing he'puried ammonia.

moniaoal vapors from the still through the' preheated liquor to the scrubber.

apparatus for treating gas liquor comprising an ammonia still, -a -preheater for the gas liquor, means for scrubbing the preheated gas liquor with the ammonia glven off yfrom the ammonia still, and a.

phenol absorber arranged to remove the phenolic compounds from .the ammonia, escaping from the still before it comes in contact with the preheated gas liquor.

5. An. apparatus for treating gas liquor.

comprismg an ammonia still, a preheater for the gas liquor anda countrdahcurrent scrubber, the ammonia still having free and fixed ammonia sections and the scrubberbeing arranged for the circulation of the liquor therethrough after it leaves the ree ammonia section and before it enters the fixed ammonia section, and means for passing vapors from the free ammonia still through the scrubber.

6. An apparatus for/treating gas liquor for the recovery of ammonia, comprising a preheater, a scrubber, an ammonia still and' means between the ammonia still and the scrubber for condensing water vapor and phenol compounds and introducing them into the scrubber.

7. An apparatus for treating gas liquor comprising an ammonia still, a preheater for the gas liquor, means for scrubbing the preheated gas liquor, a 'dephle ator for condensing water vapor and p enol comy pounds, a connection between the ammonia still and dephlegmator, a 'connection between the to of the dephlegmator and the scrubber and) means for introducing condensed water and phenol compounds which accumulate in the dephlegmator into the top of the scrubbing means.

In testimony whereof we affix our signatures.

LE ROY WILBUR HEFFNER.` WILLIAM TIDDY.

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